DirectoryAdded

Runs after you add a working directory mid-session with the /add-dir command, or after an SDK client adds one with the register_repo_root control request. Use this to prepare a newly added repository, for example by installing its dependencies.

Claude Code doesn't fire this event when:

• You pass a directory with the --add-dir startup flag; SessionStart covers those directories
• You add a directory on the /permissions Workspace tab
• You add a directory that is already a working directory or inside one

Claude Code fires DirectoryAdded after refreshing sandbox and permission state, so sandboxed tools already see the new directory when your hook runs. Hook commands themselves run unsandboxed.

Claude Code doesn't wait for the hook: the add completes immediately, and the hook runs in the background with the 600-second default timeout.

The matcher filters on how the directory was added:

Matcher	When it fires
slash_command	You add a directory with /add-dir
register_repo_root	An SDK client adds a directory with the register_repo_root control request

DirectoryAdded input

In addition to the common input fields, DirectoryAdded hooks receive directory and source.

Field	Description
directory	Absolute path of the directory that was added
source	How the directory was added, "slash_command" for /add-dir or "register_repo_root" for the SDK control request

{
  "session_id": "abc123",
  "transcript_path": "/Users/.../.claude/projects/.../transcript.jsonl",
  "cwd": "/Users/my-project",
  "hook_event_name": "DirectoryAdded",
  "directory": "/Users/my-other-repo",
  "source": "slash_command"
}

DirectoryAdded hooks have no decision control. They can't block the add, which has already completed when the hook runs. Claude Code discards the continue field from their JSON output and surfaces the rest differently per source:

• slash_command: Claude Code delivers the hook's systemMessage to Claude as context on the next conversation turn, rather than showing it to you. A count of failed hooks appears in the transcript. Full failure output goes to the debug log
• register_repo_root: Claude Code writes systemMessage output and failure output to the debug log only